Lepton Flavor Model from Delta(54) Symmetry

Abstract

We present the lepton flavor model with $Δ(54)$, which appears typically in heterotic string models on the $T^2/Z_3$ orbifold. Our model reproduces the tri-bimaximal mixing in the parameter region around degenerate neutrino masses or two massless neutrinos. We predict the deviation from the tri-bimaximal mixing by putting the experimental data of neutrino masses in the normal hierarchy of neutrino masses. The upper bound of $\sin^2θ_{13}$ is 0.01. There is the strong correlation between $θ_{23}$ and $θ_{13}$. Unless $θ_{23}$ is deviated from the maximal mixing considerably, $θ_{13}$ remains to be tiny.